This application is based on and incorporates herein by reference Japanese Patent Application NO. 2000-303282 filed on Oct. 3, 2000.
The present invention relates to an automatic vehicle headlight optical axis adjusting apparatus for automatically adjusting the optical axis of illumination from headlights provided in a vehicle.
It is proposed to ensure forward visibility of a vehicle by measuring distance to a preceding vehicle ahead thereof using a laser radar device and adjusting the optical axis of headlights up to the extent that the headlights do not blind a driver of a vehicle far ahead.
In one system disclosed in JP-A-10-151987, light distribution is changed so as to avoid directing the illumination light of the headlights to the detected preceding vehicle. However, in order to change part of the light distribution of the headlights the headlights and associated structure unavoidably become complicated and expensive. In addition, drivers of preceding vehicles to the right and left sides are blinded due to the light distribution characteristics of the headlights if the optical axis of the headlights is raised according to the distance to the vehicle that is directly ahead of the vehicle.
The present invention therefore has an object to provide an apparatus for automatically adjusting an optical axis of vehicle headlights so that forward visibility can be improved.
According to the present invention, distance to a forward or preceding vehicle in plural side-to-side zones of a specific angular range is detected as forward information for the vehicle. The desired optical axis raising angle for a vehicle headlight is calculated according to these inter-vehicle distances. The desired optical axis raising angle is the most downward pointing angle. It is therefore possible to control upward optical axis adjustment without complicating a system configuration and without blinding a driver of a preceding vehicle, and forward visibility can be improved by appropriately controlling adjustment of the optical axis of the headlight.
Preferably, a modular laser radar device is used to scan a specific angular range side to side for information in front of the vehicle, all preceding vehicles in the angular range can be detected.